X-ray tube.



J.-M. PREGENZER.

X-RAY TUBE.

APPLICATION FILED mus. 1916.

liatentml' Jan. 15, 1918.

dry 79.

JOSEPH M. PBEGENZER, OI CHICAGO, ILLINOIS.

x-RAY TUBE.

Specification of Letters Patent.

Application filed January 5, 1810. Serial No. 10,870.

I To all whom it may concern:

Be it known that I, Josnrn M. PREGENZER, a citizen of the United States of Ame ica, and a resident of Chicago, county of 00k, and State ofIllinois, have invented certain new and useful Improvements in X-Ray Tubes, of which the following is a specification.

This invention relates to Roentgen ray generators or X-ray tubes, and especially to that part of the tube-or neck which is adjacent to the cathode, which part heretofore has been subject to a serious tendency to break down under the action of the heat gen erated at the cathode;-

The main objects of this invention are to 'provide improved means for increasing the durability of X-ray tubes; to ,provide impro ed means for protecting the glass wall of t e tube adjacent to the cathode from the heat there enerated; to provide a durable heat-proof acket or shield between the neck wall and the cathode, and surrounding the latter, whereby the glass wall may be screened from the direct rays of heat from the cathode; and to provide a jacket so formed and arranged as to furnish a circulation ap orspace on both sides whereby the rarefi gases. in the tube may circulate through the neck past the cathode on the inside andoutside of the jacket, preferably in opposite directions respectively, and so temer the heat near the cathode and prevent injury to the adjacent wall of the tube.

An illustrative embodiment of this invention is shown in the accompanying drawings, 1nIwhich-. 1 i X igure 1 is]; perspective view of an -ray tube embodyingthis invention.

Fig. 2 is an enlarged vertical axial section through the cathode and jacket and adjace'nt members, parts of which are shown fragmentarily. V v

In the construction shown in the drawmgs, the shape and general apfiearance-of the bulb or tube 1 is substanti y like that of tubes used heretofore, except for the jacket or shield 2. and the mountin means therefor in the lower part of the tu The anode 3 is electricallyconnected to the posi-' tivaterminal 4 which is sup c ted by the tubularfprojection 6;, Thecat ode 6 is mounted on the terminal rod"! disposed in the tubular extension 8 whereby the current .leaves' the anti-cathode 9'is mounted on the inner end of a massive bar 10'he1d in the i tubular projection 12, said bar 10 also being connected to the positive side of the source of current, and constituting an additional anode. The members 3and 10 are electrically connected b the means 15 attached to the termina s 4 and 16, The vacuum regulator 17 disposed on one side of the tube does not constitute any part of the present invention. The same 1s true of the anode and anti-cathode members. g

The cathode 6 is concave on its upwardly facing active side and is formed and disposed in such manner as to focus \the cathode rays emanating therefrom on the anti-cathode plate 9 which is the source or origin of the X-rays. .Said plate 9 is disposed at an angle for directing the X-rays laterally as customary in X-ray tubes. Said cathode is somewhat saucer-shaped and isvattacheddemountably on the inner or upper end of the terminal rod 7. Said rod except adjacent to its upper end is inclosed in a tubu ar lass covering 19, which projects inward mm the lower end or bottom of said extension 8 of the X-ray tube, saidrod 7 being sealed in the glass, as will be understood. The circular edge of the flarin sides of the cathode is disposed at or near t e neck of the tube, nearly opposite the point 20 where the downward projection 8 meets the main body of the X-ray tube, said edge being comparatively near the glass wall of the tube.

The shield member or heat screen 2is cup shaped and is disposed concentrically about thecathode 6, being spaced somewhat therefrom. The bottom of said shield 2 is formed with a downwardly extending cylindrical part or contracted tubular stem 22 fitting closely upon-the rod 7. The lower extremlty of said stem is enlarged somewhat at 23 so as to receive. and fit tightly upon the upper end of the tubular casin 19 which sur- Patented Jan215,j1918.

"rounds and supports the r0 7. The u per 4 end of the rod 7 is screwed into the cat ode member 6 at 25 so that the latter may be removed readily for lacing the shield 2 on,

shieldthus servin as'a jacket for dir'ectin I the circulation. e intense heat genera at the cathode 6 tends to cause: the rarefied gases in the 01111 2 to. rise within the cup,

whereupon thereis, a tendencg for circular tion of'the gasesdownward a j scent to walls of the tube on the opposite side of the cup wall. The jacket 2'thus serves 1n two ways to protect the walls of the tube adjacent. to the cathode, first b screening the wall from the direct rays 0 heat from the cathode, and second by promoting a circulation of whatever gases there may be in the tube so as topro'duce a cooling effect on the walls of the tube opposite the cathode. This removal of heat by gaseous convection is assisted by conduction in the shield which carries some of the heat downward to the rod 7 and glass support 19..

The shield or jacket 2 may be of any durable material adapted to withstand the heat, but is preferably made of metal, steel being found preferable, being durable and adapted for ready manufacture at a low cost, and bein free from oxidization in the vacu'ous cham er of the X-ra tube. Metal. has a further advantage, for t e reason that, being a good conductor of heat, it assists most effectively by conduction to remove the excess of heat from the zone surrounding the edges of the cathode.

The anode and cathode members are preferably made of aluminum, which is "*li ht and combines both commercial and practical efficiency The anti -cathode late which must be refractory to withstamf heat generated by the focused cathode rays,

is ireferably made of platinum.

ltho'ugh but one specific embodiment of this invention is herein shown and described,

it will be understood that numerous details of the construction shown may be altered or the intense omitted without departing from the s irit ing claims.

claim 1. I In an X-ray tube, tween the cathode and said shield bein disposed medial y a shield disposed bethe wall of the tube, cup-shaped with its walls between the cathode and the wall of the tube in spaced relation thereto respectively, and the lower part of said shield being aperturedto permit circulation of gas through said shield acting as a jacket.

2. An X-ray tube having a main body part and a tubular projecting part, a cathode disposed at the juncture of said body part and projecting posed between said cathode and the adjacent part of'said tube in spaced relation to each, and downwardly extending heat conducting means supporting said shield.

part, and a shield disa of this invention as defined by the fol ow- 3. A metal jacketed cathode comprising JOSEPH M. PREGENZER.

more or less at the bottom 

